الفهرس 
Review of LiteratureOnly 14 pages are availabe for public view
 |  | from | 63 |  |  |
| | | from | 63 | | |
Abstract
Effectiveness of some pre-harvest spraying treatments on yield, quality and
extending of storage life of Washington Navel orange fruits.
This investigation was carried out during the two successive seasons of (2007 and
2008) to examine the effectiveness of pre-harvest spraying of some treatments on yield,
fruit quality and storability of Washington Navel orange fruits. Orange trees used in this
study are 25-years-old budded on sour orange, grown in clay soil in an private orchard at
kafr El-Dawar region, EL-Behira governorate, Egypt. Trees received normal horticultural
practices including: surface irrigation, fertilization, pruning as well as pest and disease
control. The trees were planted at (4.0 × 4.5) meters apart.
The following treatments were carried out:
1- Control (sprayed with water only).
2- Vitamin C (Ascorbic acid) at 6 %.
3- Vitamin C (Ascorbic acid) at 12 %.
4- Yeast at 1 g/liter.
5- Yeast at 3 g/liter.
6- Sucrose at 0.20 %.
7- Sucrose at 0.30 %.
8- Gibberellic acid at 100 ppm.
9- Gibberellic acid at 200 ppm.
Three foliar sprays were carried out on trees from each treatment as follows:
The first application was just after 35 and 40 days from full bloom for Washington
Navel orange trees. The second application was after three weeks from the first one, and
the third application was after three weeks from the second. At maturity stage fruits were
picked and stored under cold condition (5˚ C with 90-95 % RH). Every 20 days fruit
samples were taken to be analyzed for both physical and chemical characteristics during
storage periods.
The following determinations were obtained:
1- Yield :
53
- All treatments increased the yield per tree in both seasons more than control.
- In two season of study, vitamin C at (6 % and 12 %), sucrose at (0.20 % and 0.30 %) and
Gibberellic acid at (100 ppm and 200 ppm) were more effective than the yeast at (1 g per
liter and 3 g per liter) on yield.
2- Fruit weight:
- All treatments increased fruit weight in both seasons more than control. In addition,
vitamin C at (6 % and 12 %), sucrose at (0.20 % and 0.30 %) and Gibberellic acid at (100
ppm and 200 ppm) were more effective than the yeast at (1 g per liter and 3 g per liter) on
fruit weight.
3- Weight loss percentage:
- All treatments decreased fruit weight loss percentage compared with control.
- Vitamin C treatments at (6 % and 12 %) are more effective on decreasing fruit weight
loss percentages compared with other treatments.
4- Fruit disorder percentage:
- All treatments reduced fruit disorder percentage more than control. In addition, the
higher concentrations from Gibberellic acid, sucrose and yeast were more effective in
reducing fruit disorder percentages.
5- Total soluble solids (TSS):
- All treatments increased fruit total soluble solids compared with control.
- Gibberellic acid treatments in two seasons of this study are more effective on increasing
total soluble solids content, except for yeast at 1 g per liter in the first season.
6- Vitamin C:
- All treatments increased ascorbic acid compared to control.
- Vitamin C treatments at (6 % and 12 %) and sucrose at (0.20 % and 0.30 %) were more
effective than that other treatments on increasing ascorbic acid (mg per 100 ml juice).
7- Acidity:
- All treatments decreased fruit juice acidity compared with control.
54